Dental instrument



Feb. 24, 1953 c, c, KEIGER 2,629,172

DENTAL INSTRUMENT Filed May 29 1950 IN V EN TOR.

C. C. KEIGER ATTORNEY Patented Feb. 24, 1953 UNITED STATES PATENT OFFICE DENTAL INSTRUMENT Cyrus 0. Keiger, Charlotte, N. C.

Application May 29, 1950, Serial No. 164,933

1 Claim.. (01. 32-63) l This invention relates to dental instruments and more particularly to a novel instrument especially designed for use in connection with the filling of cavities in teeth.

The present application is primarily concerned with the filling of cavities in the labial surfaces of the teeth commonly referred to as incisors and canines and in the buccal surfaces of the bicuspids and molars.

The vast majority of fillings required for cavitiesof this character are formed from plastic materials. The cavity is first prepared and then the plastic material is introduced thereinto. Pressure is required to insure that the plastic material has completely filled the cavity and this pressure must be maintained constant until the plastic material has hardened, precluding any possibility of movement of the filling until the plastic material has finally set in proper position. Approximately five minutes setting time is required for the plastic materials with which we are here concerned and, during this time interval, movement of the patients head or the dentists instrument may result in ruining the filling. Where the cavity in question is especially closev to the gum, this situation is further aggravated. 7

Instruments have been designed whereby appropriate pressure upon plastic fillings may be maintained, however, the successful use of such instruments depends on the ability of both patient and dentist to avoid relative movement during the setting interval.

It is accordingly a major object of the present invention to provide a novel and improved dental instrument whereby appropriate pressure may be providedwith particular ease upon the labial and buccal surfaces of the teeth, to insure the proper filling of cavities therein. I

. It is a further object of the invention to provide a novel set of dental instruments including a plurality of selectively interchangeable spoonshaped instruments especially designed for engagement with the labial and buccal surfaces of the teeth.

It is a further object of the invention toprovide a novel dental instrument of the class set forth which will include an especially conformed handle to permit the more convenient grasping and secure retention of the instrument in the hand of the user.

It is a further object of the invention to provide a novel dental instrument of the class set forth which will include a plurality of specially conformed handles and compressors to provide 55 jaws,

ready and convenient access to the labial and buccal surfaces of all teeth.

It is a still further object of the present invention to provide novel locking means, for use in connection with a dental instrument of the class set forth, which will insure stability and prevent possibility of inadvertent movement of the instrument with respect. to the tooth surface to which it is applied.

It is a still further object of the present invention to provide a novel dental instrument of the class set forth which may be readily used, will be particularly light in weight, will be strong and durable, and may be economically manufactured.

Further objects and advantages of the invention will be apparent from the following specification, taken in conjunction with the accompanying drawing, wherein:

Fig. 1 is a fragmentary perspective view illustrating the novel dental instrument of the present application in use;

Fig. 2, a vertical sectional view through the disclosure of Fig. 1, illustrating the instrument locked in proper position for the filling of a labial cavity in an incisor in the upper jaw, the lower jaw being omitted;

Fig.3, a perspective view illustrating the instrument removed from the upper jaw of Fig. 2, a portion of the locking mold being broken away for the sake of clarity;

Fig. 4, a perspective view of the instrument handle and spoon-shaped compressor of Figs. 1 through 3, illustrating these parts in detached or expanded relationship;

Fig. 5, a perspective view illustrating a handle especially conformed for mounting a spoonshaped instrument intended for use as a com pressor in connection with buccal fillings;

Fig. 6, a perspective view illustrating a modi-. fied form of handle especially conformed for mounting a spoon-shaped instrument also intended for use as a compressor in connection with buccal fillings;

Fig. 7, a perspective view illustrating, on an enlarged scale, the spoon-shaped instrument designed for'use in connection with fillings in the buccal surfaces of teeth located in the upper right and lower left hand sides of the jaws; and

Fig. 8, a perspective view illustrating, on the same enlarged scale, the spoon-shaped instrument designed for use in connection with fillings in the buccal surfaces of teeth located in the upper left and. lower right hand sides of the With continued reference to the drawing, there has been disclosed in Figs. 1 and 2 the jaw J of a patient, teeth T being illustrated somewhat conventionally. One of the incisors in the upper jaw has been illustrated as having a cavity C in which there has been positioned a plastic filling F, the novel dental instrument of the present invention being shown in proper position for compressing the. plastic filling during the setting interval.

The preferred embodiment of the invention illustrated includes several handle portions or members of different exterior conformation, three being illustrated. One of these handle members is primarily intended for use in connection with the filling of labial cavities while the remaining two handle members are intended for use in connection with the filling of buccal cavities.

With particular reference to Figs. 1 through 4 of the drawing, the handle I is designed for use in connection with labialfillings and is manufactured from any suitable relatively light weight material, being substantially fiat and comparatively thin. This handle member terminates in a rounded lower extremity H, for convenient grasping, and includes inwardly tapered side walls l2 which provide a relatively narrow intermediate portion I3 beyond which the side walls gradually flare outwardly to form an enlarged portion I' l adjacent the opposite extremity of the handle. Beyond this enlarged portion the side walls l2 taper sharply inwardly, as indicated at l2", thev upper extremity of the handle member being provided with an axial bore l5, internally screw-threaded for engagement with th complementarily threaded extremity It of a labial compressor I'i.

The compressor H]. is substantially axially aligned with. the threaded extremity or stem-like shaft l6 and is preferably spoon-like in cross sectional contour to provide a concave surface l8 intended for engagement with the convex labial surface of the tooth being filled.

In the use of the dental instrument thus described, thecavity C'is first prepared for filling, in the usual manner and as is well known in this profession, and the plastic filling material F is then introduced into the prepared cavity. Appropriate pressure must then be applied to the plastic fillingmaterial, to insure that the cavity is completely filled, and such pressure must be maintained constant until the material has set in final form. This pressure is provided by the concave surface it of the spoon shaped compressor l1 and novel locking means. is provided for assuring the retention of the. compressor in proper position against the labial surface of. the tooth bei'n g Such locking means comprises a relatively small quantity of soft molding wax, or similar material, which is placed upon the handle member l0 in surrounding relationship with respect to the enlarged portion i3 thereof- Simultaneously with the application of pressure. upon the filling F'by the concave surface. Id of the compressor 'l-l, the molding wax W is pressed. into engagement with the teeth immediately adjacent to the one being filled. The wax W is immediately chilled; becoming hard relatively instantaneously and forming a rigid mold M which surrounds the handle of the instrument and locks the compressor in proper angular relationship upon the plastic filling. Manual separation is then required; to:- remove mold and instrument from the patients mouth, it being particularly simple to permit the device to remain in position the necessary time interval required for the setting of a plastic filling, without any discomfort to the patient. The mold is then removed from the handle, without difficulty, and discarded, the instrument being ready for further use.

In practice it has been found particularly convenient to place the spoon-shaped compressor l'l against the tooth surface, after the cavity has been prepared. The wax mold is then prepared and the instrument removed from the patients mouth. Plastic filling material is then inserted into the prepared cavity and the locking mold engaged. with the appropriate teeth. Mold and compressing instrument will remain securely in position, exerting proper pressure against the plastic fillingjuntilv such material has set in desired position, at which time the instrument is removed and thereafter the mold'is discarded.

A substantially identical process is employed in connection with the filling of cavities in the buccal surfaces of bicuspids and molars, it being necessary to provide appropriately contoured compressors and, preferably, differently shaped handles to permitof maximum ease of operation.

To this end there has been provided anespecia-ll-y conformed handle member l9, manufac tured from any suitable relatively light weight material, intended for use inconnectionwith the filling of cavities in buccal surfaces. Like the handle member hi, the handle 9 is substantially fiat and comparatively thin. As will be more readily apparent from an examination of. Fig.. 5 of the drawing, the handle 19 includes a relatively straight side wall 20, a gently arcuate opposite side-wall 2'! providing an enlarged base portion adjacent the bottom wall 22, and angularly disposed top walls 23 and 24 providing, with the upper extremity of the side 21, an angularly offsetextremity 25. Theend wall 24 of. thisofiset extremity is provided with an internally screw threaded bore 2t intended for engagement with the complementarily threaded extremity 28 ofa buccal compressor 29-. A similar internally screw-threaded bore 21' is provided the side wall 26 of the handle l9 immediately" adjacent the enlarged base portion, intended for selective engagement with the c'omplementarily threaded extremity 2 3 of a buccal compressor,v as will. be hereinafter'morefully described.

A minimum of two buccal compressors are re.- quired, oppositely conformed for use upon teeth upon the left and right hand sidesof the jaws. Such aproblem isnot present inaconnecti-on with the labial compressor which functionswith identical accuracy upon both top and bottom teeth. Two such buccal compressorsare illustrated in Figs. '7 and f the-drawing.

Referring first to Fig. 7, thecompressorifi is preferably spoon-like in cross sectional contour to provide a concave surface 3U intendedfor'engagem'ent with the convex buccal surface" of the tccthbeing filled. A- goose neck 31 is provided, between the compressor 29 and the threaded ex tremity or stem-like shaft 23, the compressor being angul'arly disposed with respect. to: said extremity. i-his buccal compressor. which is illustrated in Fig. 5-as positioned in the angular extremity of the handle [9, isintended for'usein connection with the filling of cavities in the buccal surfaces of the upper left and lower right bicuspids andmolars, it being only necessary to reverse the position of the handle: from that illustrated as; between. teeth inthe upper or lower jaw. Any angular: adjustment maybe obtained between the compressor and the handle by reason of the threaded association therebe tween, the locking mold serving to maintain this adjustment during the interval required for setting the plastic filling. Moreover, to attain a vastly different angular relationship between compressor and handle, the threaded extremity 28 of the compressor 28 may be engaged within the bore 2'! adjacent the opposite end of the han die is, thus providing more convenient access to buccal surfaces of molars farthest removed from the incisors and which may require attention.

The buccal compressor 32 illustrated in Fig. 8

of the drawing includes a concave portion 33 and is intended for use in connection with the filling of cavities in the upper right and lower left bicuspids and molars. The compressor 32 is substantially the reverse of the compressor 29 and includes a goose neck portion a l terminating in a screw-threaded stem-like shaft 35 identical to the stem-like shaft 28. With the compressor 32 positioned in the angularly offset extremity 25 of the handle IS, the instrument is ready for engagement with the buccal surface of the appropriate upper right bicuspid or molar. Reversal of the position of the handle is required if the tooth being filled is located in the left hand side of the lower jaw. Where the buccal surfaces of molars farthest removed from the incisors require attention, or for different angular adjustments as may be required from time to time, the compressor 32 need only be positioned in the bore 2? adjacent the opposite extremity of the handle 19.

It will be understood that the handle l9 and the buccal compressors 29 and s2 are used in the identical manner described hereabove in connection with the handle 10 and the labial compressor Ii. Preferably, the cavity is first prepared and the required angular adjustment of compressor and handle is determined following which the locking mold i completed. Plastic filling material is then inserted into the prepared cavity and the buccal compressor is returned to locking position where it is permitted to remain, with substantially no discomfort to the patient, until the completion of the time interval required for'setting the plastic filling.

There has been illustrated in Fig. 6 of the drawing a third form of handle intended for use under conditions where a relatively narrow straight handle is preferable. This handle 36 is preferably polygonal in exterior conformation, to permit of ready grasping, and terminates at the upper extremity thereof in a gently tapered frusto-conical portion 31 provided with an internally screw-threaded axial bore 38 intended for selective engagement with the complementarily screw-threaded extremities of the several compressors, the exterior diameters and screwthreads of all of these extremities being preferably identical. It will be obvious that the handle 36 may be conveniently employed with the labial compressor IT or with either of the buccal compressors in accordance with required conditions.

It is contemplated that a larger number of compressors, both labial and buccal may be provided to complete the novel dental instrument contemplated herein. These compressors may vary insofar as size, angular inclination and convexity are concerned and will thus be widely adaptable for use upon large or small teeth so as to accurately conform to the contour thereof as well as to the precise location of the cavity. Further, the instrument lends itself to a wide variety of uses, as will be readily apparent to those skilled in this profession among which are the cementing in position of prepared porcelain or metallic fillings, the taking of impressions in connection with the preparation of the type of filling commonly referred to as an inlay, and the cementing of such a fillin in position. It has been found in practice that the instrument functions with a maximum degree of efficiency and is especially adaptable for use where fillings are required at or immediately adjacent the gum line where, ordinarily, upward pressure that is particularly painful to the patient is necessitated during the time required for the setting of a filling formed from plastic material and, where porcelain or related fillings are being completed, the possibility of cementitious substances adhering to the under surface of the gum is obviated.

It has also been contemplated that handles and compressors may be manufactured integrally and such instruments have functioned highly satisfactorily in accordance with the teachings of the instant application. However, for maximum adjustability as well as versatility to compensate for angular eccentricities found in teeth as a rule rather than as an exception, a conveniently adjustable relationship between compressor and handle, obtained by either frictional or threaded engagement, has been considered preferable.

It will be obvious to those skilled in thi art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawing and described in the specification but only as indicated in the appended claim.

What is claimed is:

A dental matrix tool comprising a member having a concave tooth engaging surface, a stem laterally offset and projecting from and secured to said member in a plane inwardly of the filling engaging portion of the concave surface, and a handle for securement to said stem whereby a lateral pressure may be applied to the tooth when said handle is moved in the direction faced by the concave surface, said handle and member being guidable into a fixed position by means of a plastic material surrounding the handle and which is shaped to engage the teeth for fixing the position of the tool during the setting process of the tooth filling material.

CYRUS C. KEIGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 550,508 How Nov. 246, 1895 1,410,311 Howe Mar. 21, 1922 1,505,684 Ainsworth Aug. 19, 1924 2,196,896 Dvorak Apr. 9, 1940 2,491,050 McAdoo Dec. 13, 1949 FOREIGN PATENTS Number Country Date 100,647 Australia Apr. 8, 1937 

